The present invention relates to a headlamp that is installed on the front of an automobile and is used to illuminate the road surface and the like. Particularly, the invention relates to a headlamp that can effectively utilize the light from the light source.
In the present specification and claims, xe2x80x9ca road surface and the likexe2x80x9d refers to a road surface and persons and objects on the road surface.
In recent years, there have been developed headlamps of which luminous intensity distribution pattern changes based on the move of a sub reflector.
A headlamp of this type has been disclosed, for example, in U.S. Pat. No. 5,060,120. This headlamp includes a light source, a fixed main reflector, and a movable sub reflector. When the light source of this headlamp has been turned on, the main reflector and the sub reflector reflect the light emitted from the light source. The reflected light irradiates the road surface and the like in a target luminous intensity distribution pattern. The luminous intensity distribution pattern changes based on a move of the sub reflector. According to this headlamp, apart of the main reflector forms a reflection surface that reflects the light from the light source to the sub reflector.
The present invention relates to an improvement in the headlamp, and has an object of providing a headlamp that can effectively utilize the light from the light source.
In order to achieve the above object, according to the present invention, a main reflector and a sub reflector are prepared based on a composite combination of reflection surfaces of free curved surfaces. The sub reflector is movably disposed at a position where the light from the light source is directly incident to the sub reflector, and also at the position where the sub reflector does not interrupt a light path through which the light from the light source is incident to the main reflector.
As a result, according to the present invention, the light from the light source is directly incident to the sub reflector, and also the light from the light source is incident to the total reflection surface of the main reflector without being interrupted by the sub reflector. Therefore, it is possible to effectively utilize the light from the light source.
Other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.